Stringent requirements govern the accuracy of medical robotic devices or, in other words, devices that are able automatically to perform a movement or automatically to prevent defined movements of the device during an operating intervention. Accuracy here refers to how precisely a device may approach a predetermined position and/or may take up the position. If the absolute position of the device is measured and compared with the desired position, any difference is a measure of the accuracy. The accuracy of a medical robotic device may be a function of the position the device takes up and a speed with which the position is taken up. In the case of multiaxial medical robotic devices with many degrees of freedom, (in other words many movement options that are independent of one another), the accuracy of the device is a function of the kinematic configuration of the device or its axes. In principle, devices with a large number of degrees of freedom are also advantageous in medical applications, as they allow a high level of flexibility to be achieved with regard to positional accuracy, (in other words in respect of the space problem in many operating scenarios).
With multiaxial devices, in extreme instances referred to as singularities, very significant inaccuracies and even behavior that may no longer be predicted may result. A singularity is defined here in accordance with the ANSI safety standard ANSI/RIA R15.06-1999 as a condition that may be ascribed to a collinear alignment of two or more axes of a robot and results in unpredictable movement and movement speeds of the robot.